Transcript Spreadsheet vs Database

Spreadsheet vs Database
• When do we use them?
Spreadsheet review
• Why do we use a spreadsheet?
Spreadsheet review
• Enter data
• Do calculations on data
• Examples: expenses, profit/loss
Expenses
Gradesheet
Database
• Store information long-term
• Search information
An example…
• What sort of information does Ren Da Fu
Zhong need to keep?
• Think of at least 10 pieces of information!
RDFZ stores information on…
• Students:
– Name, address, ID number, parents, grades,
classes, teachers, payment info, absences,
extra activities
• Teachers:
– Name, address, ID number, classes taught,
students taught, grades given, bank
information, payment information
RDFZ stores information on…
• Other employees:
– Name, job, hours worked/week, pay scale,
bank information, duties/responsibilities
• Inventories:
– How many classrooms, how many desks,
chairs, overhead projectors, scanners,
computers…
RDFZ stores information on…
• Lots of stuff!
• Can all of this fit on one spreadsheet?
– No!
– This is when we use a database.
Uses of a database
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Store data
Backup data
Add/Modify data
Query data (ask questions)
Generate reports (print data in an easy-toread format)
Examples of databases
• Can you think of any?
Your music
Your games
Your web pages
Your life
Warning!
• Databases are very different from word
processors, spreadsheets, or presentation
software.
• You CANNOT just start typing.
• A database must be DESIGNED before
you start adding data.
• Why?
Why?
• Avoid duplication (putting in the same data
many times)
• Logical organization of data
The parts of a database
• Do you remember:
– Columns?
– Rows?
– Cells?
• These have different names in a
database… 
Table: one page
Column = Field
• We have 3 fields: ID,
title, and date
• Notice – every field
has the same data
type!
• This is required!
Data Type review
• Remember these
from Excel?
Row = Record
• Here we have 4 records
• Each record has all the information from one
entry.
Another example
• Here we have 3 records
• A record has all the info on one entry
Cell: Data Value
• How many data values are in this table?
Primary Key
• Here, the “Video Collection” field is the primary
key
• EVERY table MUST have a primary key – a
unique value
Primary Key Examples
Designing a Database
• Before we enter data, we must design the
table
• Things to think about:
– What fields do we need?
– What data type does each field need?
– Which field can become the primary key?
Example: RDFZ
• What information will RDFZ store about
students?
• What data type should each be?
• Which field will make a good primary key?
Example: Taobao business
• We are running a business on TaoBao.
We are selling clothing on the internet.
We want to make a database of all the
orders that we receive.
• What information must we store?
• What data type should each field be?
• What should be the primary key?
Example: a new home
• We are real estate agents, and need to
build a database of all apartments in the
area.
• What information must we store?
• What data type should each field be?
• What should be the primary key?